Numerical Simulation of Heat Transfer in Firefighters' Protective Clothing with Multiple Air Gaps during Flash Fire Exposure

Ghazy, Ahmed; Bergstrom, Donald J.

doi:10.1080/10407782.2012.666932

Cited by 70 publications

(44 citation statements)

References 20 publications

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“…The absorption coefficient of air,k a is 5 m À1 [27]. The absorptivity, a t and emissivityε, and the absorption coefficient of the mixed gas k t for the air gap can be given by:…”

Section: Rte For the Air Gapmentioning

confidence: 99%

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Modeling of heat and moisture transfer within firefighter protective clothing with the moisture absorption of thermal radiation

Yuan

Weng

2015

International Journal of Thermal Sciences

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“…The absorption coefficient of air,k a is 5 m À1 [27]. The absorptivity, a t and emissivityε, and the absorption coefficient of the mixed gas k t for the air gap can be given by:…”

Section: Rte For the Air Gapmentioning

confidence: 99%

“…It can be assumed that the heat transfer for the air gap is combined conduction and radiation. Therefore, the energy conservation equation of each air gap is given as below [27].…”

Section: Radiation Of the Boundary For The Fabric Layermentioning

confidence: 99%

Modeling of heat and moisture transfer within firefighter protective clothing with the moisture absorption of thermal radiation

Yuan

Weng

2015

International Journal of Thermal Sciences

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“…Good matching between model predictions and experimental measurements was found. Subsequently, Ghazy and Bergstrom [7,8] developed a thermal model of the protective gear composed of a single-layer fire resistant fabric [7] and of three fabric layers separated by two air gaps [8]. They dealt in a more sophisticated way with the air gap between the fabric and the sensor (skin simulant) than in the previous models [1][2][3][4][5][6].…”

Section: Introductionmentioning

confidence: 99%

“…The problem of mathematical and numerical modelling of transport phenomena in the protective garments was undertaken many times [1][2][3][4][5][6][7][8][9][10][11][12][13][14]. However, the complex nature of heat and mass transfer phenomena in the multilayer protective clothing resulted in many simplifications which were introduced into proposed heat and mass transfer models.…”

Section: Introductionmentioning

confidence: 99%

Verification and validation of an advanced model of heat and mass transfer in the protective clothing

Łapka

Furmański

2018

Heat Mass Transfer

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The paper presents verification and validation of an advanced numerical model of heat and moisture transfer in the multi-layer protective clothing and in components of the experimental stand subjected to either high surroundings temperature or high radiative heat flux emitted by hot objects. The developed model included conductive-radiative heat transfer in the hygroscopic porous fabrics and air gaps as well as conductive heat transfer in components of the stand. Additionally, water vapour diffusion in the pores and air spaces as well as phase transition of the bound water in the fabric fibres (sorption and desorption) were accounted for. All optical phenomena at internal or external walls were modelled and the thermal radiation was treated in the rigorous way, i.e., semi-transparent absorbing, emitting and scattering fabrics with the non-grey properties were assumed. The air was treated as transparent. Complex energy and mass balances as well as optical conditions at internal or external interfaces were formulated in order to find values of temperatures, vapour densities and radiation intensities at these interfaces. The obtained highly non-linear coupled system of discrete equations was solved by the Finite Volume based in-house iterative algorithm. The developed model passed discretisation convergence tests and was successfully verified against the results obtained applying commercial software for simplified cases. Then validation was carried out using experimental measurements collected during exposure of the protective clothing to high radiative heat flux emitted by the IR lamp. Satisfactory agreement of simulated and measured temporal variation of temperature at external and internal surfaces of the multi-layer clothing was attained.

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“…Then, Ghazy and Bergstrom (2011) further investigated the influence of the conduction-radiation in the gap between protective clothing and the skin on the overall performance of the clothing. Ghazy and Bergstrom (2012) also developed a model for heat transfer in multiple layers firefighters' clothing that considers the combined conduction-radiation heat transfer within the air gaps between clothing layers. Ghazy (2013) developed a novel air gap model that stands middle way between the conduction-radiation model introduced in Ghazy (2011) and the approximate air gap model exists elsewhere in the literature.…”

Section: Introductionmentioning

confidence: 99%

Influence of Thermal Shrinkage on Protective Clothing Performance during Fire Exposure: Numerical Investigation

Ghazy¹

2014

MER

Self Cite

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The thermal shrinkage of protective clothing during fire exposure plays a crucial rule in reducing the clothing protective performance. The transversal reduction in the fabric perimeter around the body due to the fabric thermal shrinkage causes a dynamic reduction in the air gap between the clothing and the body. This leads to a dynamic change in the heat transfer modes within the gap. Despite of its influential effect on the clothing performance, the thermal shrinkage of protective clothing during fire exposure has not been yet addressed in the literature. This can be attributed to the absence of a gap model that can capture the reciprocal change in heat transfer modes within the gap due to clothing shrinkage. This paper develops a finite volume model to investigate the influence of the fabric thermal shrinkage on protective clothing performance. A special attention was drawn to the model of the air gap between the clothing and skin as it responds directly to the clothing thermal shrinkage. The influence of a variation in the fabric shrinkage rate and the overall reduction in the fabric dimensions was investigated. The paper demonstrates that the clothing protective performance continuously decreases with the reduction in the fabric dimensions while the decay in the clothing protective performance is limited to small shrinkage rates of the fabric. Moreover, this decay in the clothing performance vanishes at high shrinkage rates of the fabric.

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Numerical Simulation of Heat Transfer in Firefighters' Protective Clothing with Multiple Air Gaps during Flash Fire Exposure

Cited by 70 publications

References 20 publications

Modeling of heat and moisture transfer within firefighter protective clothing with the moisture absorption of thermal radiation

Modeling of heat and moisture transfer within firefighter protective clothing with the moisture absorption of thermal radiation

Verification and validation of an advanced model of heat and mass transfer in the protective clothing

Influence of Thermal Shrinkage on Protective Clothing Performance during Fire Exposure: Numerical Investigation

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